The material and physical universe consists of four planes of matter, or four great octaves of vibration, each differentiated from the other as in our physics prakriti is differentiated from ether. The material universe, the ancient physics teach, was originally pure thought, Manasa, the product of the spiritual planes above. This manasic world was differentiated, a real world. That is to say it was given elementary substances by the union of its atoms in different sized molecules. Some of its elements combined and formed Prana. The prana gathered and formed other worlds, pranic worlds. Then in the pranic world etheric worlds were formed; and finally in the etheric worlds, prakritic globes like the earth were formed. The earth is the centre of a prakritic globe, revolving in ether around the sun. The sun is the centre of a solar globe of ether, revolving in prana around Alcyone. Alcyone is the centre of a stellar globe of prana revolving in manasa around the central and hidden sun of the great manasic globe. These four conditions of matter prakriti, ether, prana, and manasa are the earth, water, fire, air of the Ancient Metaphysics, the four elements of matter, and are present in every atom of prakriti. When the atom of prana was formed, it had an envelope of manasa. When the atom of ether was formed it had an envelope of pranic-manasic atoms. When the prakritic atom was formed it had an envelope of etheric-pranic- manasic atoms, each of its encircling etheric atoms being the centre of a pranic molecule, and each pranic atom of that molecule being the centre of a manasic molecule. Each atom of prakriti was the material universe in miniature. It held the potentialities of mind, life, and phenomena. In every aggregation of atoms, there were the four planes, each in touch through the Cosmic Mind, its manasa, with other atoms in the universe, with every other globe of whatever kind. "As above, so below," was the secret Key-word. The unity of all the material universe in its prakriti, ether, prana and manasa, was the corner stone of this knowledge. The three planes above prakriti were called Astral, and in common speech there was the ordinary division into two planes, visible and invisible, or "Spirit," as the invisible was called, and "Matter," as the visible was called. Only in the hidden secret doctrine of physics, and in the open metaphysics which were a "stumbling block" and "foolishness" to those who had not the "inner light" of the physics, were the three divisions of the "astral" made known, and the true distinction between the spirit of the three higher planes and the matter of the four lower was kept out of the metaphysics, or only vaguely alluded to.